I want to translate the following into French:
When I had signed the letter, Maurice mailed it.
I would write this: "Quand j'avais signé la lettre, Maurice l'a envoyée."
What I want to do is avoid the pluperfect in the subordinate clause. l reached for the usual stand-by "Après avoir/être + past participe" but that will not work here, as there are two subjects and "Après avoir signé la lettre, Maurice l'a envoyée" means "After having signed the letter, Maurice mailed it" but it also means that Maurice both signed it and mailed it. I have always used "Après avoir ..." in the context of there otherwise being one subject.
I then tried "Après que ..." but I still end up with the pluperfect because inescapably the signing of the letter is complete and precedes the posting of it by Maurice. Then I thought to use the passive, but that seems generally to be anathema to the French and it is really clumsy to try it here. Then I thought to change the exact English formulation of the sentence and use "J'ai signé la lettre et puis Maurice l'a envoyée" but I don't think that that helps (or is correct). The signing precedes and is complete before Maurice's action and I keep ending up with the obvious - passé composé for Maurice's action and plus-que-parfait for the action that preceded it (signing).
Any solution please to re-write the original in a way that avoids using the pluperfect in the subordinate clause?